Development of an assay for Mg-dechelatase of oilseed rape cotyledons, using chlorophyllin as the substrate

Vicentini, Fabrizio; Iten, Felix; Matile, Philippe

doi:10.1034/j.1399-3054.1995.940109.x

Cited by 28 publications

(43 citation statements)

References 7 publications

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“…Different types of activities Plant Mol Biol (2013) 82:505-517 509 have been described in the past, one attributed to a heatstable low-molecular weight compound, termed metalchelating substance (MCS) (Shioi et al 1996a;Suzuki and Shioi 2002), the other attributed to heat-labile proteins, termed Mg-releasing proteins (MRP) (Suzuki and Shioi 2002;Vicentini et al 1995b). However, MRP activity could so far only been shown when using chlorophyllin, i.e.…”

Section: Mg-dechelation and Dephytylationmentioning

confidence: 99%

Update on the biochemistry of chlorophyll breakdown

2012

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In land plants, chlorophyll is broken down to colorless linear tetrapyrroles in a highly conserved multi-step pathway. The pathway is termed the 'PAO pathway', because the opening of the chlorine macrocycle present in chlorophyll catalyzed by pheophorbide a oxygenase (PAO), the key enzyme of the pathway, provides the characteristic structural basis found in all further downstream chlorophyll breakdown products. To date, most of the biochemical steps of the PAO pathway have been elucidated and genes encoding many of the chlorophyll catabolic enzymes been identified. This review summarizes the current knowledge on the biochemistry of the PAO pathway and provides insight into recent progress made in the field that indicates that the pathway is more complex than thought in the past. Abstract In land plants, chlorophyll is broken down to colorless linear tetrapyrroles in a highly conserved multistep pathway. The pathway is termed the 'PAO pathway', because the opening of the chlorine macrocycle present in chlorophyll catalyzed by pheophorbide a oxygenase (PAO), the key enzyme of the pathway, provides the characteristic structural basis found in all further downstream chlorophyll breakdown products. To date, most of the biochemical steps of the PAO pathway have been elucidated and genes encoding many of the chlorophyll catabolic enzymes been identified. This review summarizes the current knowledge on the biochemistry of the PAO pathway and provides insight into recent progress made in the field that indicates that the pathway is more complex than thought in the past.

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Section: Mg-dechelation and Dephytylationmentioning

confidence: 99%

Update on the biochemistry of chlorophyll breakdown

2012

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“…Chlorophyllins were prepared from chlorophylls by Molisch conversion as described by Vicentini et al (1995). One hundred µl of 30% KOH in methanol was added to 12 ml of chlorophyll solution in petroleum ether.…”

Section: Preparation Of Chlorophylls and Chlorophyllins For Enzyme Asmentioning

confidence: 99%

“…The dechelation of magnesium from chlorophyllin (or chlorophyllide) to form pheophorbide was determined by monitoring the change in absorbance with time at 686 nm according to Vicentini et al (1995) and Janave (1997). The assay mixture was comprised of 830 µl 50 mM Tris-Tricine (pH 8.0), 50 µl chlorophyllin (A 686 nm = 0.18), 100 µl of 1% Triton X-100, and 20 µl of enzyme extract.…”

Section: Preparation Of Chlorophylls and Chlorophyllins For Enzyme Asmentioning

confidence: 99%

“…Natu-ral chlorophyll a degradation in senescent plants occurs by one of two pathways: one is pheophorbide a pathway (Matile et al, 1999) and the other is oxidative bleaching pathway (Janave, 1997). Three in vitro enzyme assays for quantifying chlorophyllase, oxidative bleaching, and Mg-dechelatase activities involved in the two pathways have been described previously (Vicentini et al, 1995;Janave, 1997). In contrast, herbivore-or pathogen-elicited leaf chlorosis in growing plants is not well understood.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic change in photosynthetic pigments and chlorophyll degradation elicited by cereal aphid feeding

Quisenberry

Heng-Moss

et al. 2002

Entomologia Exp Applicata

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The concentration of photosynthetic pigments (i.e., chlorophylls a and b, and carotenoids) and chlorophyll degradation enzyme (i.e., chlorophyllase, oxidative bleaching, and Mg‐dechelatase) activities on aphid‐damaged and non‐damaged regions of the infested leaves were determined with two infestation periods (6 and 12 days). Russian wheat aphid [Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae)] feeding caused significant losses of chlorophylls a and b and carotenoids in the damaged regions. However, bird cherry‐oat aphid [Rhopalosiphum padi (L.) (Hemiptera: Aphididae)] feeding did not, except a significantly lower level of carotenoids was observed in the damaged regions from the short‐infestation (6‐day) samples. Interestingly, the non‐damaged regions of D. noxia‐infested leaves on both sampling dates had a significant increase of chlorophylls a and b and carotenoid concentrations when compared with the uninfested leaves. Although D. noxia feeding did not cause any changes in either chlorophyll a/b or chlorophyll (a+b)/carotenoid ratio between the damaged and non‐damaged leaf regions on short‐infestation (6‐day) samples, a significantly lower chlorophyll a/b ratio was detected in long‐infestation (12‐day) samples. The assays of chlorophyllase and oxidative bleaching activities showed no significant differences between the damaged and non‐damaged regions of the infested leaves on either sampling date. Mg‐dechelatase activity, however, was significantly higher in D. noxia‐damaged than non‐damaged leaf regions from the short‐infestation samples, while no differences were detected from the long‐infestation samples. Furthermore, the long‐infestation samples showed that Mg‐dechelatase activity from both D. noxia‐damaged and non‐damaged regions increased significantly in comparison with the respective regions of either uninfested or R. padi‐infested leaves. We infer that non‐damaged regions of D. noxia‐infested leaves compensate for the pigment losses in the damaged regions, and that Mg‐dechelatase activity changed dynamically from a localized response to a systemic response as infestation duration extends. The findings from this study on cereal aphid‐elicited chlorosis (or desistance) would help us to elucidate plant resistance mechanisms, in particular plant tolerance to non‐defoliating herbivory.

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“…chelating substances (MCS) or by Mg-releasing proteins (MRP), which differs by their substrate specificity. 19,20 We found that A9:u-ATP9 and ap3:u-ATP9 plants presented an increase of 25 and 40% of the Mg-dechelatase activity respectively compared with wild-type plants (Fig. 3).…”

mentioning

confidence: 88%

Mitochondrial dysfunction affects chloroplast functions

Busi

Gómez-Lobato

Araya

et al. 2011

Plant Signaling & Behavior

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Plants require the contribution of three different genomes found in separate compartments. Chloroplasts and mitochondria, which are of endosymbiotic origin, contain only relatively few proteins encoded by their own genomes, following the transfer of a great part of the genetic material from the prokaryotic ancestors into the nucleus of the host. Consequently, most of the mitochondrial and chloroplast proteins are nuclear-encoded, synthesized in the cytoplasm and imported into organelles. [1][2][3] Given that several cellular functions are performed by proteins encoded in different compartments, the existence of mechanisms that coordinate the expression of nuclear and organellar genes should be necessary. One important question concerns the character (identity) of the signals responsible for interorganellar cross-talk able to direct the expression of a set of nuclear genes.The intercompartment cross-talk includes anterograde (nucleus-to-organelle) and retrograde (organelle-to-nucleus) controls. Anterograde mechanisms are responsive to endogenous and environmental signals received by the kernel and coordinate the expression of genes in chloroplasts and mitochondria. Retrograde signaling regulates the expression of nuclear genes in response to the physiological state of organelles. Besides the cross-talk between chloroplasts/mitochondria and nucleus, interactions between chloroplast and mitochondria has been established during the evolution of plants to coordinate the activities of the two organelles which exhibit a high degree of metabolic independence 4 ( Fig. 1). Profound changes in gene expression of nuclear-encoded genes were observed in Arabidopsis plants exhibiting impaired mitochondrial function. [5][6][7][8][9][10][11][12] The recent study of the transcriptomeThe transcriptomic response of A9:u-ATP9 and apetala3:u-ATP9 lines carrying a mitochondrial dysfunction in flower tissues has been characterized. Both lines showed an alteration in the transcription of several genes involved in carbon and nitrogen metabolism, stress responses, transcription factors and DNA binding proteins. Interestingly, several transcripts of photosynthetic-related genes were also affected in their expression such as the mRNAs encoding for chlorophyllase, chlorophyll binding proteins and a PSII. Moreover, chlorophyll levels were reduced and the Mg-dechelatase activity was increased, indicating an alteration in chlorophyll metabolism. Our results suggest that the mitochondrial dysfunction may also affect chloroplastic functions, and that our model could be useful to uncover retrograde signaling mechanisms operating between the three different plant genomes. Keywords: mitochondria, chloroplasts, mitochondrial dysfunction, arabidopsis in Arabidopsis plants carrying a mitochondrial dysfunction, revealed important modifications in the expression of some genes from the carbon metabolic pathways with inhibition of glycolysis and the induction of the MDH alternative pathways. Mitochondrial dysfunction affects chloroplast functions 13This mo...

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Development of an assay for Mg-dechelatase of oilseed rape cotyledons, using chlorophyllin as the substrate

Cited by 28 publications

References 7 publications

Update on the biochemistry of chlorophyll breakdown

Update on the biochemistry of chlorophyll breakdown

Dynamic change in photosynthetic pigments and chlorophyll degradation elicited by cereal aphid feeding

Mitochondrial dysfunction affects chloroplast functions

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